ML20133H432
| ML20133H432 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 08/05/1985 |
| From: | George Thomas PUBLIC SERVICE CO. OF NEW HAMPSHIRE |
| To: | Knighton G Office of Nuclear Reactor Regulation |
| References | |
| GL-83-28, SBN-855, NUDOCS 8508090350 | |
| Download: ML20133H432 (3) | |
Text
,
George S. Thomas
)
b
\\ L - --- i Vice President-Nuclear Production
.o d
}
O dU SEN-855 T.F. B4.2.99 New Hampshire Yankee Division August 5, 1985 United States Nuclear Regulatory Commission Washington, DC 20555 Attention:
Mr. George W. Knighton, Chief Licensing Branch No. 3 Division of Licensing
References:
(a) Construction Permits CPPR-135 and CPPR-136, Docket Nos. 50-443 and 50-444 (b) USNRC Letter dated June 18, 1985, " Request for Additional Information Following Preliminary Staff Review of Public Service Company of New Hampshire's Response to Generic Letter 83-28", G. W. Knighton to R. J. Harrison
Subject:
Additional Information Regarding Generic Letter 83-28 Items 4.2.1 (Periodic Maintenance Program for Reactor Trip Breakers) and 4.2.2 (Trending of Reactor Trip Breaker Parameters to Forecast Degradation of Operability)
Dear Sir:
In response to the referenced request for additional information, we bave enclosed a description of Seabrook Station's periodic maintenance program for reactor trip breakers.
Items 1-3 of this description address the concerns raised with respect to Generic Letter 83-28 item 4.2.1; Generic Letter 83-28 item 4.2.2 is addressed by item 4 of the enclosed description.
Responses to Generic Letter 83-28 iteme 2.1, 3.2.3, 4.5.2 and 4.5.3 will be supplied in future submittals, consistent with the schedule set forth in Reference (b).
.Very truly yours, George Thomas GST/cjb Enclosure cc: ASLB Service List O
i t
8508090350 850805
~
PDR ADOCK 05000443 A
PDR P.O. Box 300 Seabrook,NHO3874 Telephone (603)474-9521
' DESCRIPTION OF PERIODIC MAINTENANCE PROGRAM FOR REACTOR TRIP BREAKERS f A. planned ' program of periodic maintenance will be developed for the Seabrook Station reactor trip breakers. The program will be based on recommendations in the Westinghouse Maintenance Manual for the DS-416 Reactor Trip Circuit Breakers, Revision 0, October 1984. The program will include the features
' described below.
1.
A scheduled. inspection of the reactor trip breakers after 500' operations or six months of service, whichever comes first. This inspection will be.
performed in accordance with a written procedure which will include the following:
a.
-General inspection which includes checking of breaker cleanliness, accessable bolts and nuts, pole bases, are chutes, insulating link, r,
l' wiring and auxiliary switches;
-l b.
Retaining ring inspection, including those on the undervoltage trip attachment (UVTA) and shunt trip attachment (STA);
Arcing and main contacts inspection as specified by the Westinghouse c.
Maintenance Manual; d.
UVTA. check as specified by the. Westinghouse Maintenance Manual, including replacement of UVTA if dropout voltage is greater than 60%
or less than 30% of rated UVTA coil voltage; STA check as specified'by the Westinghouse Maintenance Manual; e.
f.
Lubricant and lubrication points as specified by the Westinghouse Maintenance Manual;.
g.
Functional check of the breaker operation prior to returning it to service.
2.
Scheduled preventive maintenance inspection of the reactor trip breakers during.each refueling outage or after 500 breaker operations, whichever comes first. These inspections will include the following:
a.
Items la g above; t-
,1 b.
Pre-cleaning insulation resistance measurement;
- c., Dusting and cleaning; 1
~d[ Post-cleaning insulation resistance measurement, as specified by the Westinghouse Maintenance Manual; l
tr
- ( ',~
r L
Inspection of main and secondary disconnecting contacts, bolt e.
tightness, secondary wiring, mechanical parts, cell switches, instruments, relays and other panel mounted devices; f.
UVTA trip force and breaker load check as specified by the Westinghouse Maintenance Manual; g.
Measurement of RTB response time for the undervoltage trip; h.
Functional test of the breaker prior to returning to service as specified by the Westinghouse Maintenance Manual.
3.
A precaution in applicable procedures to caution Maintenance personnel against undocumented adjustments or mooifications to Reactor Trip Circuit Breakers.
4.
Trend recording and evaluation of:
a.
Trip Force; b.
Breaker response time for undervoltage trip; c.
Undervoltage trip attachment dropout voltage; 1
d.
Breaker insulation resistance.
l l
l Analysis of trend information, on the 4 parameters listed above, will be performed by Maintenance Department engineers af ter each refueling inspection.
Corrective action will be initiated by the review engineer for deficient trend characteristics. This may include repair or replacement of deficient components or revision to the Maintenance procedure as appropriate.
$